Motor System (Supraspinal Control 2: Large Group Discussion (NB.037) Flashcards
3)What happen in case of imbalance between direct and indirect pathways of the basal ganglia?
- It causes hypokinetic disorders in case:
• insufficient direct pathway output
• excess indirect pathway output
3)What happen in case of imbalance between direct and indirect pathways of the basal ganglia?
-It causes hyperkinetic disorders in case
• excess direct pathway output
• insufficient indirect pathway output
Hypokinetic disorders that may result from damage to the basal ganglia?
Parkinson’s disease; prevent movement initiation.
Hyperkinetic disorders that may result from damage to the basal ganglia? And exactly what structure is damaged in each?
-ballism (damage to the subthalamic nucleus)
-Huntington’s disease (degeneration of striatal cholinergic and GABA-ergic neurons)
What is ballism?
Hyperkinetic disorder due to damage to the subthalamic nucleus
What is Huntington’s disease?
-type of neurons affected
Hyperkinetic disorder due to damage to the degeneration of striatal cholinergic and GABAneurons
Factors affecting the intensity of Static Tremor in Parkinson’s?
(at rest), affecting one or both hands, the fingers in a pill-rolling motion, may affect tongue, legs, jaw. ↓ by movement & absent during sleep↑ by emotional tension or fatigue.
What’s the pathology:
- Difficulty in initiating rapid fine movements. shuffling gait (slow to start , small steps), reduced arm swinging, impaired balance on turning .
Hypokinesia
Define Rigidity in terms of:
-effect on posture
-effect on facial expression
-effect on speech
-effect on reflexes
3-Rigidity (↑muscular tone):
-Stiffness and flexed posture
- Mask face (loss of facial expression)
- Slow monotonous speech
-No hyper-reflexia as the tone is high in flexors and extensors
Medical treatment for Parkinson’s?
Surgical treatment for Parkinson’s?
Effect of Thalamotomy on bradykinesia & rigidity?
bradykinesia usually remains, and rigidity improves variably
Effect of “Electro coagulation of ventrolateral nucleus of thalamus” on tremor?
tremor resolves on the contra lateral side
Why is Pallidotomy considered as one of the surgical treatments for PD?
to remove its basal inhibition on thalamus and cortex
Risky complications of Pallidotomy?
And why do they happen?
has risks: including blindness and hemiparesis, due to the proximity of the pallidum to other critical structures (the optic tracts and internal capsule).
What is Deep Brain Stimulation?
Define Athetosis
Characterized by continuous, slow writhing movements
What is the pathophysiology of chorea?
3 causes of chorea ?
1- As a complication for rheumatic fever (Sydenham’s chorea), self limited –no dementia.
2- Congenital (Huntington’s chorea): Progressive dementia-fatal (Dementia means decreased memory and cognitive function)
3-May occur in females due to toxemia of pregnancy.
What is Sydenham’s chorea?
chorea As a complication for rheumatic fever
2 clinical presentations of chorea?
1-Hypotonia and pendular knee jerk
2-Involuntary movements: sudden purposeless dancing movements of arms, legs, face, head and trunk (↑by emotions and ↓ by sleep).
What causes hemiballismus?
clinical presentation of Hemiballismus? 2 points
1- Hypertonia.
2-Involuntary movements: Attacks of rapid violent movements (half of the body) ➔ may cause loss of balance.
may be fatal due to spasm of the respiratory muscles.
A fatal complication of Hemiballismus?
2-Involuntary movements: Attacks of rapid violent movements (half of the body) ➔ may cause loss of balance.
= “may be fatal due to spasm of the respiratory muscles”
Meaning of the word Athetosis?
What causes athetosis ?
- region and type of neurons affected
Lesion in lentiform nuclei mainly globus pallidus
(degeneration of GABA releasing neurons projecting to the thalamus).
clinical presentation of Athetosis ? 2points
Lesion in vestibulocerebellum (archicerebellum) leads to?
Lesion in cerebrocerebellum leads to?
Neocerebellar syndrome
Causes of Neocerebellar syndrome? Are the associated affections contra or ipsilateral?
C/P of Neocerebellar syndrome?
I- Motor ataxia
II- Athenia
III- Hypotonia
Definition of Motor ataxia?
Complications of Motor ataxia?
What is Asynergia?
Inability to perform two voluntary acts at the same time due to loss of co-ordination between different muscle groups
What is Dysmetria?
(Inability to control distance of movement ): movement overshoot the intended point
What is Dysdiadochokinesia?
loss of predictive function and slow initiation) :
inability to do rapid and alternating opposite movement
What is Dysarthria?
scanning or stacatto speech due to decomposition of movements, loss of coordination and prediction of buccal, laryngeal, and respiratory movements
What is Nystagmus?
Involuntary, rapid oscillation of the eyeballs in a horizontal, vertical, or rotary direction, with the fast component maximal toward the side of the cerebellar lesion
Define Asthenia and it’s cause
What is Hypotonia
Compare between sensory ataxia and motor ataxia in terms of:
-proprioceptive sensations.
-sign on closing eye.
- Compensation by vision
-tremors
- Nystagmus
-Dysarthria
-GAIT
Function of Inferior Olivary Nucleus? In three points
